A once-prominent Republican lawyer in Chicago, Illinois, who served brief but notable tenures as a federal prosecutor and state attorney general, has sadly passed away.

Tyrone Fahner, who led the prestigious Mayer Brown law firm after serving as the Illinois attorney general under a Republican governor, died this week at the age of 81, according to CBS News.

He garnered statewide and national prominence by prosecuting political corruption in Chicago in the 1970s as a federal prosecutor and led a task force that investigated the unsolved "Tylenol murders" that plagued the city in the early 1980s.

Loss mourned by his former law firm

The Mayer Brown law firm announced on Tuesday, "With a very heavy heart we mourn our friend, colleague, and former Chair, Ty Fahner. He was 81."

Among his achievements, the Memorium noted that Fahner "led the firm through a time of incredible growth and change" as a co-chair from 1998 to 2001 and then as chairman from 2001 to 2007, and oversaw successful mergers with other prestigious national and international law firms.

"In recent years, Ty continued to be involved in the Chicago community through his considerable civic and charitable work and, most recently, served as a key advisor to our former partner, Lori Lightfoot, during her tenure as Mayor of the City of Chicago," the firm added. "Ty’s contributions -- to the state of Illinois and to this Firm -- are many. Our deepest condolences go out to the entire Fahner family, and the many people that called Ty partner and friend."

Was an anti-corruption federal prosecutor and Illinois attorney general

According to the Chicago Tribune, Fahner was born in Detroit, Michigan, to a union autoworker father and telephone operator mother, and earned an education that included a bachelor's degree from the University of Michigan, a law degree from Wayne State University Law School, and a masters degree from Northwestern University School of Law.

While at Northwestern, he studied under James Thompson and, when Thompson became the U.S. Attorney for the Northern District of Illinois, followed him to become an Assistant U.S. Attorney, where he headed the official corruption unit and most famously prosecuted influential Chicago Alderman Thomas Keane, the chair of the City Council’s Finance Committee, on mail fraud and conspiracy charges in the mid-1970s.

After his stint as a federal prosecutor, Fahner briefly returned to private practice as an attorney but was quickly recalled into public service when Thompson was elected as Illinois' Republican governor in 1976.

He was appointed by Thompson as the director of the Illinois Department of Law Enforcement and served two years in that role, then stepped away again before being appointed by the governor as the Illinois attorney general to replace his predecessor, William Scott, following a conviction for tax evasion.

In 1982, Fahner mounted a campaign to be elected to a full term as the AG but was sidetracked from that political effort that he ultimately lost by his focus on investigating the so-called "Tylenol murders" in 1982 that caused a panic when at least seven Chicago residents died from ingesting Tylenol pills laced with cyanide. Though the murders were never solved, the case led to pharmaceutical companies developing tamper-resistant packaging for over-the-counter medications.

Served as a mentor and advisor to future elected Democratic officials

After his relatively brief service in politics, Fahner returned to private practice again and joined Mayer Brown as a partner, according to the Chicago Sun-Times, where in addition to eventually leading the firm he also displayed bipartisanship and served as a mentor to other members who would go on to become elected Democratic officials.

One of those was former Chicago Mayor Lori Lightfoot, who said, "Ty was a kind and generous friend who was a significant support to me at every stage of my career" and "helped me understand how to be a good lawyer and professional." She added, "Despite our superficial differences, we shared a deep bond as two working-class kids trying to make our mark in the world, and I am forever grateful that when I was so young, Ty saw something in me and a lifelong bond was forged."

Another prominent Democrat mentored by Fahner is Illinois Senate President Don Harmon, who said his mentor "believed in public service and encouraged people, including myself, to pursue it regardless of party," and added, "Even when you disagreed with him, and over the years I often did, you knew he was intellectually honest and his heart was in the right place."